The immune system is a complex response system of the body that involves many different kinds of cells that have differing activities. Activation of one portion of the immune system usually causes a variety of responses due to unwanted activation of other related portions of the system. Currently, there are no satisfactory methods or compositions for producing a specifically desired response by targeting the specific components of the immune system.
The immune system is a complex interactive system of the body that involves a wide variety of components, including cells, and cellular factors, which interact with stimuli from both inside the body and outside the body. Aside from its direct action, the immune system's response is also influenced by other systems of the body including the nervous, respiratory, circulatory, and digestive systems.
One of the better-known aspects of the immune system is its ability to respond to foreign antigens presented by invading organisms, cellular changes within the body, or from vaccination. Some of the first kinds of cells that respond to such activation of the immune system are phagocytes and natural killer cells. Phagocytes include among other cells, monocytes, macrophages, and polymorphonuclear neutrophils. These cells generally bind to the foreign antigen, internalize it and often times destroy it. They also produce soluble molecules that mediate other immune responses, such as inflammatory responses. Natural killer cells can recognize and destroy certain virally—infected embryonic and tumor cells. Other factors of the immune response include complement pathways, which are capable of responding independently to foreign antigens or acting in concert with cells or antibodies.
Generally, it is thought that the response to antigens involves both humoral responses and cellular responses. Humoral immune responses are mediated by non-cellular factors that are released by cells and which may or may not be found free in the plasma or intracellular fluids. A major component of a humoral response of the immune system is mediated by antibodies produced by B lymphocytes. Cell-mediated immune responses result from the interactions of cells, including antigen presenting cells and B lymphocytes (B cells) and T lymphocytes (T cells).
One of the most widely employed aspects of the immune response capabilities is the production of monoclonal antibodies. The advent of monoclonal antibody (Mab) technology in the mid 1970s provided a valuable new therapeutic and diagnostic tool. For the first time, researchers and clinicians had access to unlimited quantities of uniform antibodies capable of binding to a predetermined antigenic site and having various immunological effector functions. Currently, the techniques for production of monoclonal antibodies are well known in the art. However there remains a continuing need for specialized antibodies. In essence, what is desired is the ability to produce customized antibodies. The need is especially great in the area of combating infectious disease where pathogens have acquired resistance to commonly used antibiotics. In addition, there is a need for antibiotics, for addressing pathological conditions resulting from cause other than an infectious agent.
Alzheimer's Disease (AD) is a neurological disorder primarily thought to be caused by the build of amyloid plaques caused by abnormal deposit of proteins in the brain. Scientific evidence demonstrates that AD results from an increase in the production or accumulation of beta-amyloid protein in plaques that leads to nerve cell death. Loss of nerve cells in strategic brain areas, in turn, causes reduction in the neurotransmitters and impairment of memory. The proteins principally responsible for the plaque build up include amyloid precursor protein (APP) and two presenilins (presenilin I and presenilin II). The degradation of APPs likely increases their propensity to aggregate in plaques. There is a need for specific antibodies that can target and diffuse amyloid plaque formation.
The symptoms of AD manifest slowly and the first symptom may only be mild forgetfulness. In this stage, individuals may forget recent events, activities, the names of familiar people or things and may not be able to solve simple math problems. As the disease progresses, symptoms are more easily noticed and become serious enough to cause people with AD or their family members to seek medical help. Mid-stage symptoms of AD include forgetting how to do simple tasks such as grooming, and problems develop with speaking, understanding, reading, or writing. Later stage AD patients may become anxious or aggressive, may wander away from home and ultimately need total care.
Presently, the only definite way to diagnose AD is to identify plaques and tangles in brain tissue in an autopsy after death of the individual. Therefore, doctors can only make a diagnosis of “possible” or “probable” AD while the person is still alive. Using current methods, physicians can diagnose AD correctly up to 90 percent of the time using several tools to diagnose “probable” AD. Physicians ask questions about the person's general health, past medical problems, and the history of any difficulties the person has carrying out daily activities. Behavioral tests of memory, problem solving, attention, counting, and language provide information on cognitive degeneration and medical tests-such as tests of blood, urine, or spinal fluid, and brain scans can provide some further information.
The management of AD consists of medication-based and non-medication based treatments. Treatments aimed at changing the underlying course of the disease (delaying or reversing the progression) have so far been largely unsuccessful. Medicines that restore the deficit (defect), or malfunctioning, in the chemical messengers of the nerve cells (neurotransmitters), such as the cholinesterase inhibitors (ChEIs), have been shown to improve symptoms. Medications are also available to address the psychiatric manifestations of AD.
Cholinesterase inhibitors, such as Tacrine and Rivastgmine, are currently the only class of agents that are approved by the FDA for the treatment of AD. These agents are medicines that restore the defect, or malfunctioning, in the chemical neurotransmission in the brain. ChEIs impede the enzymatic degradation of neurotransmitters thereby increasing the amount of chemical messengers available to transmit the nerve signals in the brain.
For some people in the early and middle stages of the disease, the drugs tacrine (COGNEX®, Morris Plains, N.J.), donepezil (ARICEPT®, Tokyo, JP), rivastigmine (EXELON®, East Hanover, N.J.), or galantamine (REMINYL®, New Brunswick, N.J.) may help prevent some symptoms from becoming worse for a limited time. Another drug, memantine (NAMENDA®, New York, N.Y.), has been approved for treatment of moderate to severe AD. Also, some medicines may help control behavioral symptoms of AD such as sleeplessness, agitation, wandering, anxiety, and depression. Treating these symptoms often makes patients more comfortable and makes their care easier for caregivers. Unfortunately, despite significant treatment advances showing that this class of agents is consistently better than a placebo, the disease continues to progress despite treatment, and the average effect on mental functioning has only been modest. ChEIs also have side effects that include gastrointestinal dysfunction, liver toxicity and weight loss.
Advances in the understanding of the brain abnormalities that occur in AD are hoped to provide the framework for new targets of treatment that are more focused on altering the course and development of the disease. Many compounds, including anti-inflammatory agents, are being actively investigated. Clinical trials using specific cyclooxygenase inhibitors (COX-2), such as rofecoxib and celecoxib, are also underway.
Another factor to consider when developing new drugs is the ease of use for the target patients. Oral drug delivery—specifically tablets, capsules and softgels—account for 70% of all dosage forms consumed because of patient convenience. Drug developers agree that patients prefer oral delivery rather than subjecting themselves to injections or other, more invasive forms of medicinal administration. Formulations resulting in low dosing intervals (i.e. once a day or sustained release) are also preferable. The ease of administering antibiotics in oral dosage forms results in an increase of patient compliance during treatment.
What is needed are effective methods and compositions for generation of highly specific and highly effective antibodies. Preferably such antibodies would recognize specific epitopes on various antigens such as amyloid protein, prion protein or P170 glycoprotein.
What is also needed therefore, are effective compositions and methods for addressing the complications associated with neurological disease associated with amyloid plaque formation such as Alzheimer's disease. In particular what is need are specialized antibodies capable of counteracting the physiological manifestations of the disease such as the formation plaques associated with aggregation of fibers of the amyloid peptide in its beta sheet conformation.